Japanese Utility Model Registration Publication No. Sho 58-37803 discloses a conventional holder 300 for a fluid filling bag illustrated in FIGS. 58(a) to 58(c). The holder 300 has two curved walls 301 and two flip plates 303, which connected by hinges 302 in upper and lower openings of the curved walls 301. One of the flip plates 303 elastically flips between an open position (convex position) and a closed position (concave position). As illustrated in FIG. 58(b), when the flip plate 303 is switched to the open position, an opening is formed in the holder 300, and a cavity 304 is formed between the two curved walls. A window 305 is formed in an end portion of the curved wall 301. This window 305 is selectively closed by a sliding plate 306. A bag 307 filled with a fluid is accommodated in the holder 300. A protrusion (lip) 308 is formed on the top surface of the bag 307, and the protrusion 308 extends through the window 305 of the holder.
When the body of the bag 307 is pressed, the fluid flows from the bag. On the other hand, by fastening the lip 308 of the bag between the sliding plate 306 and the window 305, the opened bag closes. Thus, the holder 300 retains the remaining fluid.
However, since the sliding plate 306 only opens or closes the window 305, the conventional holder 300 cannot adjust the flow rate of the fluid that flows from the lip 308.